1. Field of the Invention
This invention relates to insert pumps and tubing pumps for pumping oil from an oil well and more particularly, to a universal plunger for reciprocation inside the pump barrel of the insert pumps and tubing pumps. The universal plunger is characterized by outstanding sealing characteristics which are facilitated by the use of a polytetrafluorethylene-hydrocarbon composition seal located in the pump barrel between spaced O-rings seated on the universal plunger. The suspended polytetrafluorethylene or "Teflon" (trademark of DuPont) component of the sealing lubricant operates to coat the inside surface of the pump barrel and thereby seal the pump barrel and universal plunger against "blow back" of production fluid during pumping. The universal plunger body, O-rings and inside surface of the pump barrel thus define a sealing and lubrication chamber to facilitate highly efficient operation of a tubing or insert pump which incorporates the universal plunger of this invention.
One of the problems which exists in conventional insert and tubing pumps is that of sealing the pump plungers inside the corresponding pump barrels during reciprocation of the plungers inside the barrels. Various types of seals, including O-rings, packing and other seals well known to those skilled in the art, have been used in an attempt to increase the efficiency of the pumping operation and prevent "blow-back" of production fluid. Regardless of the type of seals and packing used to prevent, or at least minimize, this undesirable "blow-back", the pump must be periodically pulled from the well and the seals and/or packing frequently replaced, at great expense in labor and materials.
Accordingly, it is an object of this invention to provide a new and improved, liquid-sealed universal plunger for application to oil field pumps.
Another object of the invention is to provide a new and improved universal plunger for oil well pumps, which universal plunger is characterized by an elongated plunger body having a longitudinal bore and fitted with at least one O-ring on each end and also having a reduced interior body diameter for insertion in the pump barrel and receiving a polytetrafluorethylene "Teflon" resin-oil combination to seal and and lubricate the pump.
Another object of this invention is to provide a universal plunger for use in insert and tubing pumps, which universal plunger is characterized by an elongated plunger body fitted with a set of spaced O-rings on each end and an inner body segment of reduced diameter for fitting in the pump barrels of the pumps and defining a lubrication and sealing chamber for receiving a "Teflon"-hydrocarbon composition to a positively seal the reciprocating universal plunger in the pump barrel.
Still another object of this invention is to provide a universal plunger for replacing the conventional plungers in oil well pumps, which universal plunger includes an elongated plunger having a longitudinal bore and fitted with spaced seals on each end and also having an inner body portion of reduced diameter located between the seals for insertion in the pump barrel and receiving a quantity of hydrocarbon containing "Teflon" in suspension, for lubricating and sealing the universal plunger in the pump barrel.
Another object of this invention is to provide a universal plunger for insertion in the pump barrel of a tubing or insert pump, which universal plunger is characterized by an elongated, hollow pipe having at least one O-ring seal at each end, a threaded nipple projecting from each end and a body portion of reduced diameter located between the spaced O-ring seals, for receiving a quantity of "Teflon"-oil sealing and lubricating composition and retaining the "Teflon"-oil composition in the pump barrel for lubricating and sealing purposes when the universal plunger is reciprocating in the pump barrel.